Early Successes

A vaccine that prevents cancer by preventing infection by the human papilloma
virus (HPV), the cause of nearly all cases of cervical cancer, has already
been approved by the F.D.A.
The new drug is called Gardasil and was 100% effective in preventing HPV
infection in a trial of 9,000 women. Although Gardasil only works against
the two strains of HPV that cause 70% of cervical cancers, it could still
save the lives of 210,000 women per year if administered widely.

Gardasil is made from purified, inactivated proteins from the HPV virus,
which serve as the antigens that mount the immune response, and vaccination
consists of 3 shots over eight months. Because it is a vaccine against the
virus, not against the cancer cells themselves, it prevents all symptoms
of HPV infection, including genital warts.

Cervical cancer is the second-leading cause of cancer death among women,
killing 300,000 each year. About 10% of these deaths occur in the United
States, while the majority occur in Latin America and Africa. HPV infection
is still rampant in the United States, with about 6.2 million Americans
becoming infected every year and the majority of American men and women
becoming infected at some point in their lifetime. The low death rate in
the United States is due to the relative ease of detecting cervical cancers
early with regular Pap smears (a gynecological examination in which part
of the cervical tissue is scraped off and examined for signs of cancer).
If it were not for this early diagnosis, the United States would suffer
a death rate similar to Africa’s or Central America’s, and poor Americans
without access to healthcare are already in such a situation. Thus, Gardasil
has the potential to alleviate the death rate in the third world while substantially
diminishing healthcare costs in the United States.

Wider vaccination against the hepatitis B virus would also have drastic
effects on the worldwide cancer rate. Those infected with hepatitis B experience
a 20- to 100-fold increase in their risk of liver cancer, and half of all
liver cancers test positive for hepatitis B. The vaccine would be especially
useful to the people of sub-Saharan Africa and Southeast Asia, where the
virus is most prevalent. Although the vaccine has already been developed,
its use is not widespread.

There is substantial potential to decrease the
risk of stomach cancer by fighting infection as well. The Epstein-Barr
virus is known to cause stomach cancer, and researchers are in the process
of developing a vaccine against it. Heliobacter pylori is a bacterium that
infects the stomachs of about half of the people on Earth and has recently
been linked to a four- to six-fold increase in the risk of stomach cancer.

There is a good chance that active specific immunotherapy is likely to
become part of a multimodal approach to cancer. Patients will be treated
with chemotherapy and surgery in addition to vaccines. The medical profession
must get a better understanding of adjuvants administered with tumor cell
vaccines.

Oncophage

The world’s first therapeutic cancer vaccine, Oncophage,
was approved in Russia in 2008 for the treatment of kidney cancer. The United
States FDA did not approve it at that time because it found that the trials
conducted by the American developer Antigenics showed insufficient proof
of a significant benefit. Since then, the FDA has granted fast-track and
orphan drug status to Oncophage and trials are currently being conducted
for the treatment of kidney cancer, metastatic melanoma, and glioma, a form
of brain cancer.

Oncophage is produced using actual cells from the patient’s tumor to create
a specific agent to fight only the targeted cancer. In this way, healthy
tissue is left unharmed and the drastic side effects of other therapies
like chemotherapy are largely eliminated.

Prostvac and Provenge

Prostvac, another vaccine being developed to treat metastatic prostate
cancer, has been fast-tracked by the FDA and is undergoing large-scale clinical
trials. In previous trials, it has demonstrated a median overall survival
improvement of 8.5 months, but like sipuleucel-T, does not meet the criteria
for non-progressive survival.

Prostvac, unlike sipuleucel-T, is not patient-specific. It uses two viruses
along with other know immune system stimulators. The first virus is vaccinia-PSA-TRICOM,
which is injected once to ready the immune system for a response to the
cancer. The second, fowlpox-PSA-TRICOM, is administered multiple times for
continual boosting of the immune system.